Abstract: An inductor used in an RF unit for a wireless communication terminal, includes first inductor means for electrically connecting an RF chip placed over a substrate at a predetermined distance from the substrate that are enclosed by an interlayer dielectric layer and second inductor means for connecting the RF chip to the first inductor means.

Abstract: A predistorter that linearizes the nonlinearity of a power amplifier in a system supporting a multimode and a multiband (frequency band). The predistorter includes a field-effect transistor, an impedance transform unit, a first inductor, a first capacitor, and a second capacitor. The field-effect transistor has a source connected to the ground and uses a variable gate bias voltage. The impedance transform unit is connected to a drain of the field-effect transistor to perform impedance transform. The first inductor is connected between the impedance transform unit and a voltage provided to the field-effect transistor. The first capacitor is connected between a power input terminal and the impedance transform unit. The second capacitor is connected between a power output terminal and the impedance transform unit.

Abstract: Disclosed is an ultra wide band signal generator. The ultra wide band signal generator generates a signal of a required frequency using a harmonic signal having a frequency range of a ultra wide band (UWB). The ultra wide band signal generator includes an active inductor for generating harmonic signals having power strengths substantially equal to each other within a non-linear operation range, the tunable active inductor capable of tuning a value thereof, an oscillator for amplifying and outputting the harmonic signals generated from the active inductor by frequency-transiting the harmonic signals into high frequency bands, and a filter for selectively outputting one of the harmonic signals output from the oscillator.

Abstract: Provided is an apparatus and method for calibrating an imbalance characteristic of a received signal of a frequency domain in a mobile receiver which supports an Orthogonal Frequency Division Multiplexing (OFDM) scheme. To this end, a received signal of a radio frequency band is converted into a baseband signal by using a carrier, and the baseband received signal is converted from a time domain signal to a frequency domain signal. Then, a calibration coefficient is measured by using two consecutively received signals from the Fast Fourier Transform (FFT) unit. An imbalance component included in the received signal of the frequency domain due to an imbalance of the carrier is removed by using the measured calibration coefficient. In this case, the two consecutively received signals refer to two transmission signals consecutively transmitted from a transmitter, and the two transmission signals are predetermined signals.

Abstract: Provided is a multiband low noise amplifier including a first transistor, an input matching circuit, and a first capacitor. The first transistor includes a collector electrically connected to a first power supply, a grounded emitter, and a base connected to the other end of a first inductor having one end as an input end of the low noise amplifier. The input matching circuit is connected between the collector and the base of the first transistor. The first capacitor connected to the collector of the first transistior. The input matching circuit includes a varactor. The input matching circuit includes a second capacitor connected to the varactor. The input matching circuit includes a first resistor connected to the varactor. In the multiband low noise amplifier, a varactor having a variable capacitance is installed at an input end, thereby easily performing band switching through bias voltage control by a small amount and minimizing noises that may be caused by a control signal.

Abstract: An active inductor capable of tuning a self-resonant frequency, an inductance, a Q factor, and a peak Q frequency by applying a tunable feedback resistor to a cascode-grounded active inductor is disclosed. The tunable active inductor includes a first transistor having a source connected to a power supply voltage and a gate connected to first bias voltage; a second transistor having a drain connected to a drain of the first transistor and a gate connected to a second bias voltage; a third transistor having a drain connected to a source of the second transistor and a source connected to a ground voltage; a fourth transistor having a drain connected to a gate of the third transistor, a source connected to the ground voltage and a gate connected to a third bias voltage; a fifth transistor having a source connected to the drain of the fourth transistor and a drain connected to the power supply voltage.

Abstract: Disclosed is a method and an apparatus for self-calibrating a Direct Current (DC) offset and an imbalance between orthogonal signals, which may occur in a mobile transceiver. In the apparatus, a transmitter of a mobile terminal functions as a signal generator, and a receiver of the mobile terminal functions as a response characteristic detector. Further, a baseband processor applies test signals to the transmitter, receives the test signals returning from the receiver, and compensates the imbalance and DC offset for the transmitter side and the receiver side by using the test signals. The test signal is applied to only one of the I channel path and the Q channel path, and an RF band signal output from the transmission side by the test signal is used as an input signal to the reception side.

Abstract: Provided is a mixer for use in a direct conversion receiver. The mixer includes Field Effect Transistors (FETs), a current source (IBias), two load resistors (RLoad), another FET, and two inductors L1 and L2. The FET M21 constitutes a current bleeding circuitry and the other components except for the two inductors L1 and L2 constitute a so-called Gilbert cell mixer.

Abstract: Disclosed is a method and an apparatus for self-calibrating direct current (DC) offset and imbalance between orthogonal signals, which may occur in a mobile transceiver. In the apparatus, a transmitter of a mobile terminal functions as a signal generator, and a receiver of the mobile terminal functions as a response characteristic detector. Further, a baseband processor applies test signals to the transmitter, receives the test signals returning from the receiver, and compensates the imbalance and DC offset for the transmitter side and the receiver side by using the test signals.

Abstract: A switching filter module for dynamic selection of N channels is provided. In the switching filter module, each of N double-channel selection filters passes the frequency bandwidths of two of successive first to Nth channels having predetermined frequency bandwidths, and one or more 2-way and 3-way switches connect the double-channel selection filters to one another. Each of the N double-channel selection filters is serially connected to at least one of the other double-channel selection filters and at least one 3-way switch.

Abstract: A frequency mixing apparatus is provided. In the frequency mixing apparatus, a PMOS transistor is coupled to an NMOS transistor in a cascode configuration and an LO signal is applied to the bulks of the PMOS and NMOS transistors so that an input signal applied to their gates is mixed with the LO signal. High isolation between the bulks and gates of the transistors resulting from application of the LO signal to the bulks prevents leakage of the LO signal, thereby decreasing a DC offset voltage. This renders the frequency mixing applicable to a DCR. Also, due to the cascade configuration similar to an inverter configuration, the frequency mixing apparatus can be incorporated in an FPGA of a MODEM in SDR applications. Frequency mixing based on switching of a threshold voltage decreases a noise factor and enables frequency mixing in a low supply voltage range, thereby decreasing power consumption.

Abstract: Disclosed is an ultra wide band signal generator. The ultra wide band signal generator generates a signal of a required frequency using a harmonic signal having a frequency range of a ultra wide band (UWB). The ultra wide band signal generator includes an active inductor for generating harmonic signals having power strengths substantially equal to each other within a non-linear operation range, the tunable active inductor capable of tuning a value thereof, an oscillator for amplifying and outputting the harmonic signals generated from the active inductor by frequency-transiting the harmonic signals into high frequency bands, and a filter for selectively outputting one of the harmonic signals output from the oscillator.

Abstract: A predistorter that linearizes the nonlinearity of a power amplifier in a system supporting a multimode and a multiband (frequency band). The predistorter includes a field-effect transistor, an impedance transform unit, a first inductor, a first capacitor, and a second capacitor. The field-effect transistor has a source connected to the ground and uses a variable gate bias voltage. The impedance transform unit is connected to a drain of the field-effect transistor to perform impedance transform. The first inductor is connected between the impedance transform unit and a voltage provided to the field-effect transistor. The first capacitor is connected between a power input terminal and the impedance transform unit. The second capacitor is connected between a power output terminal and the impedance transform unit.

Abstract: Disclosed is a local oscillation circuit for a direct conversion receiver, which includes a local oscillator for outputting a local oscillation signal of a predetermined frequency; and a fractional signal generator for converting the local oscillation signal into a fractional harmonic signal, which has a frequency equal to a frequency of a received signal, and outputting the converted signal to a down converter. The fractional signal generator includes a divider for dividing a frequency of an output signal of the fractional signal generator by a predetermined integer; and a mixer for mixing the local oscillation signal and an output signal of the divider.

Abstract: A single chip direct conversion transceiver that includes a substrate on which a mixer unit and a local oscillator are provided as a circuit, and a positive hole formed between the mixer unit and the local oscillator and filled with a conductive plug to block signal leakage. A shield ground surface is formed above the substrate and blocks signal leakage occurring when the signals received through the antenna are input into the mixer and signal leakage occurring when the reference signal is input into the mixer from the local oscillator. A first interconnection is formed above the shield ground surface and connects the mixer unit and the local oscillator. Dielectric layers are formed between the substrate and the shield ground surface and on the shield ground surface to cover the first interconnection.

Abstract: An active inductor capable of tuning a self-resonant frequency, an inductance, a Q factor, and a peak Q frequency by applying a tunable feedback resistor to a cascode-grounded active inductor is disclosed. The tunable active inductor includes a first transistor having a source connected to a power supply voltage and a gate connected to first bias voltage; a second transistor having a drain connected to a drain of the first transistor and a gate connected to a second bias voltage; a third transistor having a drain connected to a source of the second transistor and a source connected to a ground voltage; a fourth transistor having a drain connected to a gate of the third transistor, a source connected to the ground voltage and a gate connected to a third bias voltage; a fifth transistor having a source connected to the drain of the fourth transistor and a drain connected to the power supply voltage.

Abstract: A frequency mixing apparatus is provided. In the frequency mixing apparatus, a PMOS transistor is coupled to an NMOS transistor in a cascode configuration and an LO signal is applied to the bulks of the PMOS and NMOS transistors so that an input signal applied to their gates is mixed with the LO signal. High isolation between the bulks and gates of the transistors resulting from application of the LO signal to the bulks prevents leakage of the LO signal, thereby decreasing a DC offset voltage. This renders the frequency mixing applicable to a DCR. Also, due to the cascade configuration similar to an inverter configuration, the frequency mixing apparatus can be incorporated in an FPGA of a MODEM in SDR applications. Frequency mixing based on switching of a threshold voltage decreases a noise factor and enables frequency mixing in a low supply voltage range, thereby decreasing power consumption.

Abstract: A multi-band radio frequency (RF) receiving method in a mobile communication system having a reduced size and cost includes receiving RF wave signals for four or more non-overlapping bands, primarily filtering a first wide band including adjacent first and second bands and a second wide band including adjacent third and fourth bands from the received RF wave signals, low-noise amplifying the RF wave signals of the first and second wide bands, respectively, secondarily filtering a third wide band including adjacent second and third bands and a fourth wide band including first and fourth bands from the low-noise amplified RF wave signals of the first and second wide bands, generating two band RF wave signals to be simultaneously received, and frequency-down converting the two band RF wave signals generated in the secondary filtering step into two band intermediate frequency wave signals by means of first and second oscillation frequencies.

Abstract: An apparatus for generating an in-phase/quadrature-phase (I/Q) signal in a wireless transceiver is disclosed, including a local oscillator for generating a local oscillation signal, and first and second mixers for mixing the oscillation signal with a transmission/reception signal to convert the transmission/reception signal into a baseband or high-frequency signal. The apparatus includes a phase locked circuit for controlling the local oscillator, and a polyphase filter installed between the local oscillator and the mixers, for separating the oscillation signal from the local oscillator into an I signal and a Q signal depending on a control signal from the phase locked circuit, and outputting the separated I and Q signals to the first and second mixers, respectively.

Abstract: Provided is a multiband low noise amplifier including a first transistor, an input matching circuit, and a first capacitor. The first transistor includes a collector electrically connected to a first power supply, a grounded emitter, and a base connected to the other end of a first inductor having one end as an input end of the low noise amplifier. The input matching circuit is connected between the collector and the base of the first transistor. The first capacitor connected to the collector of the first transistior. The input matching circuit includes a varactor. The input matching circuit includes a second capacitor connected to the varactor. The input matching circuit includes a first resistor connected to the varactor. In the multiband low noise amplifier, a varactor having a variable capacitance is installed at an input end, thereby easily performing band switching through bias voltage control by a small amount and minimizing noises that may be caused by a control signal.